For instance, Japanese Patent No. 3472591 discloses a substitutive cigarette. This substitutive cigarette includes a fuel element and an aerosol-generating chip. The fuel element and the aerosol-generating chip are each formed into a rod. When the substitutive cigarette disclosed in the document is smoked, the fuel element is first ignited. The burning heat of the fuel element heats the aerosol-generating chip, and the heated aerosol-generating chip generates aerosol. Such aerosol is inhaled by a smoker through a filter of the substitutive cigarette.
An aerosol-generating source disclosed in the document is produced by the following procedure.
First, filling material obtained by adding an aerosol-generating substance to particles of smoking material is prepared. Such filling material is supplied to a manufacturing apparatus with a wrapping material, or web. The manufacturing apparatus wraps the filling material in the web and forms an aerosol-generating rod. Thereafter, the aerosol-generating rod is cut into pieces of a given length, and in result, discrete aerosol-generating chips are obtained.
Since the filling material is prepared outside the manufacturing apparatus, the manufacture of substitutive cigarettes requires a preparation device for preparing the filling material in addition to the manufacturing apparatus. Equipment for manufacturing substitutive cigarettes is therefore large-scale.
For that reason, it can be considered to prepare a solution containing an additive such as an aerosol-generating substance and to add this solution to the smoking material in the manufacturing apparatus.
For the addition of the solution to the smoking material, technologies disclosed, for example, in Japanese Patent Application Publication No. 53-18800 and Japanese Patent No. 3209985 can be employed. The former technology discharges solution such as water from the inside of a tongue arranged in a manufacturing apparatus, and by so doing, prevents a gum-like film from being formed in the inside of the tongue. The tongue compresses and molds the smoking material into a rod in cooperation with a molding bed and garniture tape of the manufacturing apparatus before the smoking material is wrapped in the web.
According to the latter technology, when the smoking material is sucked in layers by a suction band of the manufacturing apparatus, and this material layer is injected with a liquid flavor additive.
However, both the technologies have only one injection position for an additive in a transfer path of the smoking material, so that they are not capable of efficiently adding the additive to the smoking material running through the transfer path at high speed.
Furthermore, if the former technology is employed, a liquid additive discharged from the tongue is contained only in the upper portion of the rod-shaped smoking material. Accordingly, when the rod-shaped smoking material is subsequently wrapped in the web, and the aerosol-generating rod is produced, a lap portion formed by superposing the side edges of the web on each other gets damp too much with the liquid additive. As a result, an adhesion defect is prone to occur in the lap portion, so that it is impossible to stably produce the aerosol-generating rod, or rod-shaped smoking article.
If the latter technology is employed, in a process of forming a material layer on the suction band, the liquid additive is injected into the material layer. Therefore, the unit length weight of the material layer becomes heavy, and moreover, the injected liquid additive hampers the suction band from sucking the smoking material. Consequently, the formation of the material layer, namely that of the rod-shaped smoking article, becomes unstable.